Blogging Theora

[xiphmont]

It's time for the latest Thusnelda encoder project update summary!

Although I haven't gotten much time to dive back into Thusnelda coding myself, Tim Terriberry, Greg Maxwell and others have continued the work along at a merry pace. In the past few weeks, they've finally replaced the leaky fDCT from the original VP3 and begun work on adjusting the main quantization matrices and, hopefully soon, adaptive quantization. These improvements all improve fine detail rendering and, somewhat unexpectedly, improve gradient rendering as well:

The screen caps above were produced by Theora 1.0 on the left and an experimental version of Thusnelda with early quant matrix optimization work in addition to the new fDCT on the right. Both clips were encoded in constant-quantizer mode and equal bitrates.

Other improvements, more details and the full update report here.

Comments

Re: Problem with older ffmpeg, not ffmpeg2theora

[(Anonymous)]

The source for libavcodec, with support for hundreds of audio and video codecs, is about 25MBs. libvorbis, and theora are each ~6MBs on their own.

Fat chance ffmpeg is going to accept a 50% increase in their code-size for one nominally popular set of codecs. Let alone all the maintenance issues. And how about performance?

Re: Problem with older ffmpeg, not ffmpeg2theora

[xiphmont.livejournal.com]

uhhh... if you're counting the configure scripts, I can't take the argument seriously. They're most of the size of any project that uses autofoo.

Compiled size would be a more accurate judge of what actually is 'getting used'. libvorbis: 210kB (AMD64). libtheora: 320kB.

Secondly, just like I said, the philosophical decision to implement their own is fine. The problem is they've done it haphazardly and show no interest in fixing bugs or maintaining the result.

I just came back from OVC where the ffmpeg people are growing a sizable body of users who would like to lynch them because they thought ffmpeg was official Ogg support and they've never gotten good results from it. Most of our advocacy at shows in the past year has been 'Oh, you're using ffmpeg. Let us show you some other tools that work properly'. ffmpeg has done as much to sabotage Ogg's reputation as Apple + Nokia combined. I'm betting that a few ffmpeg devs will read that and cheer--- and that's just indescribably sad.

Re: Problem with older ffmpeg, not ffmpeg2theora

[(Anonymous)]

By that metric, ffmpeg is also sabotaging MPEG4: the defaults are terrible and it's difficult to configure it well (this is both for its own internal ASP encoder, and for libx264 for AVC). Most videos I've seen encoded in these formats suffer quite a bit quality-wise.

OTOH, that "terrible ogg support" is probably the reason Google Chrome supports Theora+Vorbis (in addition to h.264+AAC), and I can tell you both work as well/bad as each other - for instance seeking and A/V sync do work (albeit seeking is a bit slower, it's probably suffering from the "binary search over the network" syndrome, just as Firefox did...)

Frankly this mutual hate seems overblown.